What Does It Mean When Field Quanta Are Not Spatially Localized?

[I2004]

what does it mean when someone says field quanta are not spatially localized?

does it mean they are in superpostion or they are just moving very fast?

sorry if I sound daft

 

[I2004]

and are field quanta virtual particles that pop in and out of existence?

I read "field quanta are not spatially localized since they are not excition states at a certain point of the field but have to be assigned to the field system as whole"

can someone explain why they have to be assigned to the system as a whole?


please help...

 

[Bill_K]

When describing a complex system we try to use the excitations which are simplest, namely the normal modes. For a free field the normal modes are the plane waves. A disturbance that was initially localized would not stay that way, it would spread to neighboring points and be rather difficult to deal with!

 

[I2004]

what I don't get is when it says you must take into account the whole field.

like these field quanta spread across the whole universe, because the field is everywhere...

 

[I2004]

I just don't get it when he says they are not exition states at a point in the field.

what are they then? a single quantum is spread everywhere?

please help...